When transporting perishable goods, a conventional air cargo container has inadequate insulation to maintain a controlled temperature environment, such that unacceptably high loss levels of perishable goods are encountered during transport. There are presently available refrigerated air-freight containers having a self-contained refrigeration unit, which provide effective environmental/temperature control. However, such containers are bulky and expensive, can only be used effectively for environmentally-sensitive freight, and are generally only cost-efficient for those businesses transporting extremely high cost, perishable goods.
Aside from the refrigerated containers that are presently available, there are also pre-fabricated, non-refrigerated, insulated containers, such as that disclosed in U.S. Pat. No. 4,373,643 issued to Przytarski. The insulation system is specially fabricated and becomes an integral part of the container. The interior rigid walls of the Przytarski container are lined with multiple layers of insulation including an inner layer of moisture-absorbing material, which acts as an humidity regulator, and a single layer of heat insulating material. Such prefabricated containers can be effective at maintaining controlled environments. However, like their refrigerated counterparts, these custom-designed units are expensive and are essentially dedicated to such service. They are cost-effective only when a business is solely engaged in transporting perishable goods and other specially-handled cargo.
For many transport businesses, efficient operation depends on the flexibility of handling various types of freight on a daily basis, including both freight that is environmentally sensitive and shipments that are not. Having the capability to convert a conventional container into an insulated container is advantageous to many transport businesses. Present means of such conversion are limited in their use as well as being expensive and inconvenient to install. Some conversion systems require that modifications be made to the container before the insulation system can be installed; e.g., boring a series of small holes in the sides of the container to accommodate a great many retaining hooks, from which the insulation system suspends. In addition, some systems utilize zipper fasteners to join adjacent components, thus making the system more expensive and requiring a more accurate installation of the components, translating into higher labor and loading costs. Moreover, many present systems can be installed in only certain standard containers or those of a specific shape, and do not permit the flexibility of use over a wider range of available transport containers. Another type of container-converting insulation system is taught by Baumann in U.S. Pat. No. 4,497,859. This system provides an insulating insert consisting of panels of alternating, closely-packed insulating material that are joined along their perimeters to conform to the interior of the transport container. A fluid-tight trough and bottom plate are also provided, making the system cumbersome and more difficult to install.
In light of present insulation systems, there is need for a cost-efficient and simplified insulation system that is effective at maintaining a controlled environment. Such a system must be capable of converting conventional containers into insulated containers at a minimal expenditure in time and materials, but without sacrificing the effectiveness of both the container and the insulation system. Additionally, since weight is critical for air freight, the insulation must provide these benefits without adding significant weight to the container.
It would therefore be a novel improvement to provide a freight container insulation system capable of retrofitting a conventional uninsulated freight container that includes an adhesive support means for attaching the insulation system to the interior walls of the container, a multi-layer insulated blanket affixed to the adhesive support means, covering the interior container walls to which the adhesive support means is attached, a second multi-layer insulated blanket that is draped across an access opening to the container, and an insulated sheet for placing across the bottom of the container, whereby a controlled environment is created within the confines of the container.
It would be another novel improvement to provide a freight container insulation system wherein the adhesive support means is a plurality of linear strips, constructed of an insulating material, that may be selectively sized and then affixed to the interior walls of the container in a random orthogonal fashion, and wherein the insulated blanket comprises at least one layer of a closed-cell polyethylene and at least one layer of a reflective foil laminate, which may be formed into a roll or be prefabricated and sectioned into discrete individual panels that are sized to cover a corresponding interior container wall, with the insulated sheet for the container bottom constructed of closed-cell polyethylene.
It would also be a novel improvement to provide a freight container insulation system wherein the insulation system defines a layer of air between the container walls and the installed insulation blanket, thereby incorporating the insulative qualities of air as part of the insulation system.